Prusa mendel i2 extruder settings (2 replies)

Hello all sorry but I am new to this and this is probably a silly thing to ask but, I have set my fireware for my x,y & z stepper motors but have no clue how to work out the vaule for the extruder.

I have a Sanguino 1.3a board with Atmega 1284p running Marlin firmware.

So far my setting look like this (just for information really)

#define DEFAULT_AXIS_STEPS_PER_UNIT {72.7442,72.7442,200.0*8/3,760*1.1}
________________________________________(X)_____(Y)____(Z)______(E)

Just need help with the last equation please. :S